No abstract

OBJECTIVES: Temporomandibular pain is often accompanied by pathologic changes to joint retrodiscal tissues. The substantial representation of females in this condition has encouraged hypotheses which link genetic or hormonally induced abnormalities in tissue composition (type III collagen, type I collagen, type III/type I ratio) to the development of temporomandibular disorders. As this condition is often associated with a history of orofacial trauma, we investigated the functional impact of retrodiscal trauma on the composition and biomechanics of retrodiscal tissues. DESIGN AND METHODS: Retrodiscal tissue of female goats received trauma or sham trauma. Following a healing period of 30 days, the tissues were pulled to failure on an extensometer. OUTCOME MEASURES: Assessments were made of tissue biomechanical properties (failure force, elastic stiffness, strain distribution). Tissue fragments were assayed for collagens I and III. RESULTS: Thirty days after surgical section of retrodiscal tissues, the tissue had reformed, but the composition and biomechanics were substantially changed. Healed tissue manifested less than half the strength of normal tissue (P = 0.02). In addition, the development of tissue strain shifted from a relatively even distribution to a confined region near the retrodiscal-discal attachment zone. It appeared that a large increase in the expression of type III collagen (179.6%; P = 0.038) and the ratio of type III/type I collagen (180.9%; P = 0.011) accounted for these functional changes. CONCLUSIONS: We suggest that shifts in collagen expression following injury create shifts in strain development which focus tissue stresses near the interface of the disc and retrodiscal tissue, and that this shift dramatically weakens the tissue and increases the probability of reinjury, inflammation and pain.

In 153 children suffering from various renal or urological disease a total of 179 individual and regional renal clearance studies were performed using 123-I-hippuran and a scintillation camera. The clinical diagnoses and questions before and the therapeutic consequences after clearance determinations are analyzed. The dynamic information fo sequential scintigraphy combined with renal clearance determination allow a quantitative estimation of the individual and regional kidney function. The method is considerably helpful in cases of unilateral small kidneys, obstructive uropathies, duplication of the urinary tract, and segmental renal disease.

A "region of interest" technique for measuring renal blood flow is described, using as Anger camera and selective intra-arterial injection of 133Xe and 99mTc. The sequence of measurements has the advantage of providing information on regional blood flow. The values for RBF and RBFD obtained with 133Xe agree with those in the literature. Selective determination of the RCBF with the "region of interest" technique using 133Xe was not possible. Mean transit time for 99mTc was calculated after correction of the 99mTc indicator dilution curve with respect to recirculation and background activity. All typer of pathological changes in the kidney showed a statistically significant increase in mean transit time when compared with a control group. In patients with uncomplicated essential hypertension, the mean transit time was signigicantly reduced. A comparison of the mean transit time of 99mTc with the haemodynamic parameters derived from the 133Xe studies, and experiments with pharmocologically induced vasoconstriction indicates that the mean transit time represents a measure of the RCBF.

No abstract